The present invention has particular utility as a jewelry clasp such as for securing together two ends of a chain, string or linear sections forming a continuous loop when closed. Conventionally, such devices must be opened and closed to be put on and worn. The most common locking arrangement in such devices includes providing an open loop at one end which is fitted with a solid torus while the other end includes a clasp comprising a locking torus or ring with an opening in the ring. This locking torus is generally constructed of tubular shape and has a spring pushing on a circumferentially sliding plug with a lug thereon. The locking torus has a circumferential slit in which the lug moves. The opening in this locking torus is kept closed by the spring pushing on the sliding plug and is opened by putting the fingernail on the lug and pushing back the spring thus allowing the opening in that torus to be slid over the other torus on the other end of the chain. Such operation is cumbersome particularly when it must be done on very small units. Moreover, the manipulations required must be done out of the line of sight of the user and in many cases require high digital dexterity.